One-piece sheet metal sink rim guards or the like and method for making the same



July 3, 1962 G. W. ONE-PIECE SHEET METAL Filed July 31, 1961 LENZ, JR 3,041,632

SINK RIM GUARDS OR THE LIKE AND METHOD FOR MAKING THE SAME 4 Sheets-Sheet l INVENTOR.

GEORGE W- LENZ,JR.

"4oz. smwsg July 3, 1962 5. w. LENZ, 3,041,632

ONE-PIECE ET AL SINK GUARDS OR THE LIKE ME D FOR MAKING THE SAME Filed July 31, 1961 4 Sheets-Sheet 2 INVENTOR. GEORGE W. LENZ, JR.

July 3, 1962 w, LENZ, JR 3,041,632

ONE-PIECE SHEET METAL SINK RIM GUARDS OR THE LIKE AND METHOD F OR MAKING THE SAME Filed July 31, 1961 4 Sheets-Sheet 3 a c P INVENTOR. GEORGE W. LENZ,JR.

"wt. awws July 3, 1962 ONE-PIECE SHEET METAL SINK RIM GUARDS OR THE LIKE AND METHOD FOR MAKING THE SAME Filed July 31, 1961 4 Sheets-Sheet 4 IN V EN TOR.

G w. LENZ, JR 3,041,632

GEORGE W. LENZ, JR.

. 3,041,632 oNE-PmcE srmar METAL suns RIM. GUARDS R This invention relates to an improved sink rim guard or the like and to a method for forming the same.

The conventional service sink employed, for example, in oflice buildings and elsewhere is subjected to environmental factors which frequently necessitates the employment of a rim guard. When such sink is formed of porcelain-coated metal its appearance may soon become unsightly unless means are taken to protect the rim. Cleaning personnel usually use buckets or other equipment which, upon striking the rim serve to damage the sink, and cleaning agents further tend to promote corrosion and pitting of the sink after its surface is once damaged. To avoid this problem it is customary to equip the rim of the sink with a guard made of a protective material such as stainless steel, but the forming of such a guard has heretofore involved other significant problems, and which it is a purpose of the present invention to overcome.

When the guard is formed of sheet metal as expensive as stainless steel, wastage of the stock sheet must be held to a minimum. The drawing operation upon the sheet while forming the guard must be such that the outer side of the formed guard will possess suflicient thickness to withstand repeated striking of buckets or other articles therea-gainst over a long period of time. Moreover, the number of separate steps employed in forming the guard should be as few as possible in order to reduce expense of manufacture. Attainment of each of these desirable factors is possible by the present invention, one object of which is to provide an improved one-piece sheet-metal sink rim guard.

Another object is to provide an intermediate article comprising two sink rim guards formed in a single piece and adapted for ready separation into two guards.

A further object is to provide a method for drawing sheet metal into the form of a sink rim guard.

Other objects and advantages will become apparent as the description proceeds and when considered in conjunction with the accompanying drawings in which:

FIG. 1 is a top plan view of a completed guard ready for installation;

FIG. 2 is a top plan view of the intermediate article; FIG. 3 is a plan view of the sheet metal blank from which the intermediate article is formed;

FIG. 4 is a plan view of the major portion of waste material resulting from practice of the method of the invention;

FIG. 5 is a sectional view taken on line 5-5 1 and to a larger scale;

. FIG. 6 is a vertical sectional view taken through porof FIG.

tions of a press suitable for carrying out the method and with parts shown in elevation for purposes of simplicity;

FIG. 7 is a view to a larger scale of portions of the press shown in FIG. 6 and with the intermediate article being partially formed;

FIG. 8' is a view similar to FIG. 7 and with the intermediate article being completely formed;

FIG. 9 is a detail view of a device for removing the intermediate article from the press; I

FIG. 10 is a detail view in section of certain press members used in the forming of apertures in the intermediate article; and

3,041,632 Patented July 3,1962

FIG. 11 is a sectional view taken on line 11-11 of FIG. 2 and to a larger scale. I

In accordance with the invention a generally rectangular piece of stock sheet metal is employed, and following the formation of the intermediate article,-a residual piece of sheet metal also of generally rectangular, but smaller, shape is available for use in making other types of articles therefrom. Effective usage of as much as about 87% of the material found in the original stock sheet may thus be made. The invention teaches .a method which may be conducted by a single operator employing conventional press structure and requiring apprec iably fewer steps of fabrication than found in conventional methods of manufacture, as, for example, taught by my U.S. Patent No. 2,961,663. In carrying out the invention, the sheet of stock material is interposed symmetrically between a continuous die having pinch trim sides and acommensurate die recess, the die and recess beingin the shape of a generally rectangular article of generally semi-circular cross section having a first pair of parallel straight portions and a second pair of parallel straight portions extending normally to, the first straight portions and joined thereto by arcuate corners. Upon bringing the die and recess together,the metal from the periphery of the stock sheet is drawn toward the die and the metal from the central portion of the sheet, and which central portion will later comprise the useful residual piece of metal, is stretched toward the die. The balancing of the drawing and stretching actions results in the formation of the intermediate article with outer side walls of greater thickness than the inner side walls thereof and which feature is particularly useful in sink rim guards since the outer walls of such guard are less protected during use than the inner wall thereof.

Upon being removed from the press the intermediate straight port-ions to form two similar guards from one intermediate article.

Referring now to FIGS. 3 and '4, a rectangular sheet 10 of stock material, for example stainless steel of 18 gauge, is cut from a larger continuous sheet and at its corners is suitably cut away to form arcuate edges leaving' small fragments 11, 12, 13 and 14 as scrap. The cen tral portion 15 inboard of the dotted lines representing a later formed ridge 16, will, after being subjected to certain working, form a residual piece of stock having utility in the forming of other types of articles and therefore is not considered as scrap. As seen in FIG. 4, the peripheral edge portion of the sheet 10, following the operations later to be described, will comprise a continuous rim 70 which also forms'scrap. p

The sink rim guard represented by the present invention is shown in FIG. 1 and comprises an intermediate straight portion 18 having an outer wall 19 and an inner wall 20, as related to the sink upon which the guard is to be mounted. First and second leg portions 21 and 22, respectively, project at right angles to' the intermediate portion and are parallel to each other, being joined to that intermediate portion by arcuate corners 23 and 24.

The cross section of the guard is generally semi-circular face 31 by rigid supports 32. A stationary die-supporting plate 33 rests above the base plate and both the base and die-supporting plates are provided with apertures through which a plurality of outer draw ring rods 34 and a plural proper.

3 ity ofinner draw plate rods 35 are adapted to, reciprocate. At their lower ends these rods are rigidly attachedto the movable piston 36 of a heavy duty-press actuating mecha- V nism and which piston moves within a cylinder 37 to and from wh ch a. pressurefluid, such as compressed air, may

be passed, as through a conduit 38 controlled by, any suitable valve arrangement, not shown.

At their upper ends'the rods 34 are attached to a draw ring 39 extending continuously about the outer periphery of a continuous stationary 'die of generally rectangular top planar outline. The inner edge 40' of this draw ring cooperates with the outer edge of the die to assist in a pinch trim action as will later appear, and the upper fiat surface 41 of the draw ring extends sutficiently far from the inner edge 40 to accommodate the periphery of the stock sheet when it is placed within the press structure. At their upper ends the rods 35 are attached to a draw plate 42'filling the entire planar space within the die and having an outer edge 43 cooperating with the inner edge of that die to assist in a pinch trim action. The upper surface 440i thedraw plate, moreover, provides a firm support for the reusable central portion of the stock sheet during the stretching action imposed upon that sheet.

For cooperation with the movable press portions above described, a stationary die support base ring 50 is suitably affixed to the supporting plate 33 and may be made of a softer and less expensive steel than the die portions Mounted above the base ring 50 and suitably of the sheet lying between the draw ring 39 and the member 62 outboard of the recess and the innermost of which comprises the area of the sheet lying between the draw plate 42 and the member 62 inboard of the recess. Continuing movement of the die recess toward the die then starts the formation of the intermediate article'in which the sheet 10 to be placed under tension simultaneously attached thereto is a pinch trim ring 51 of tool steel or f the like, having side edges flush with the' side edges of the base ring and terminating in upper square edges 52 and 53, as best shown in FIG. 8. Further mounted upon the pinch trim ring and suitably attached thereto is a continuous die member 54 of generally rectangular top planar outline and having a generally semi-circular cross section. The diametrical outer and inner edges of this die member are spaced inboard of the respectivesquare edges of the pinch trim ring'a sufiicient distance to accommodate the wall thickness of the intermediate article to be formed. 7 I I Referring now to FIG. 6, the press includes a movable platen suitably actuated by any conventional means, .not shown, and comprising a massive plate 60 to the underside of which is attached a punch holder plate 61; At-

tached to the underside of plate 61 is a member 62 of generally rectangular shape with an open central space a 63, and which member has a continuous die recess therein adapted for cooperation'with the continuous die 54.

This die recess has a cross section including a semi circula r portion with side legs extending tangentially thereof and terminating at a slightly beveled outer edge 64 and at a slightly beveled inner edge 65, as best seen in FIG. -9. These edges are spaced apart at a distance equal to the distance between the square edges 52 and 53 of the pinch trim ring plus the necessary clearance for movement of those recess edges past the square edges of that stationary pinch trim ring when the pinch trim action has taken place. p p With the foregoing in mind, the method of forming an intermediate article in accordance with the invention may be accomplished as follows: With the press platens fully separated, as seen in FIG. 6, and with the stock sheet 10 coated with a suitable lubricant, that sheet is symmetrically supported upon the center line of the continuous die member 54. The peripheral edge of the stock sheet preferably is at equal distances from that center line at all portions of the sheet inorder to insure a more uniform draw- -ing action, and, despite-the scrap loss which this entails, the corner portions 11 to 14 of that sheet are removed before the sheet is placed onfthe die.

across'all of its diameters, the bottom surface of that stretched central portion merely resting upon the upper surface of the draw plate 42. On the other hand, since the metal located in the peripheral edge region of the sheet 10 outboard of the edge 64 of the recess of member 62 is confined only by the pressure exerted thereon by the juxtaposed facesof the draw ring 39 and the member 62, this metal is drawn or slipped toward the die and its recess as they approach each'othcr.

This forming movement continues until the edges 64 and -65 of the recess confine the interposed material against the square edges 52 and 53 of the pinch trim ring 51, as seen in FIG. 7. Thereafter, further movement of the die recess .to bring its side walls into overlapping engagement with the pinch trim ring, trims the formed intermediate article from a thin ring of scrap such as seen in FIG. 4. This scrap may include a small upwardly directed ridge 17 correspondingto the space under the beveled edge 54 of the recess and a narrow ledge 70 corresponding to the peripheral portion of the original stock sheet. At the same time such further movement of the die recess has trimmed the intermediate article from the useful central portion 15 of the stock sheet. That useful central portion, which does not represent scrap, will iriclude a peripheral upwardly directed ridge 16 corresponding to the space under the beveled edge 65 of the recess. It will be appreciated that during the final closing movement of the die elements the drawing action upon the sheet material confined between the member 62 and draw ring 39 was productive of a greater volume of metal drawn toward the center line of the die than was the. stretching action occurring between that member 62 and the draw plate 42. The outer wall thickness of the formed article therefore is slightly greater than the inner wall thickness and this advantageous result is particularly desirable when forming sink rim guards. When carrying out the method with stock sheets of sainless steel a no ticeable work hardening of the metal occurs in the arcuate 'corners of the intermediate article and which serves to give greater rigidity to the leg portions of the final article, later to be described,

' The intermediate article thus formed is characterized by being of one continuous piece of metal; by having a hollow generally semi-circular cross section; and by having a first pair of parallel straight portions 71 and 72 and a second pair'of parallel straight portions 73 and 74 joined to each other by arcuate corners of right angle configuration, as best seen in FIG. 2. The length of the straight portions 73 and 74 moreover is such that when subdivided transversely into equal lengths along the plane P--P twoidentical sink rim guards, as shown in FIG. 1, are formed from one intermediate article.

. It will be'appreciated that the intermediate article is subjected to heavy stressing tending to confine it in the die recess during its formation by the described method and that separate means may be needed to remove the above the center line of the recess in member 62 and with a compression spring 78 interposed between that cap and the lower surface of the punch holder 61. It is found that two such knock-out devices symmetrically arranged along each straight portion of the recess and bearing upon each of the respective straight portions of the intermediate article will push that article from that recess as the upper platen withdraws fiom the lower platen.

When the invention is applied to the manufacture of sink rim guards, the automatic formation of apertures for guard fastening means may conveniently be incorporated into the forming of the intermediate article, thus to save labor in the final fabrication of the guard. As noted in FIGS. 1, 2 and 11 these apertures 80 are formed in the respective articles along the center line thereof and preferably are round and suitably counter sunk so that a bolt head passing thereinto will not mar the smooth external appearance of the sink rim guard.

As best shown in FIG. 10, each of these apertures may be formed by a corresponding punch having a flat head portion 81, a central body portion 82 and a lower punch tip 83. Each punch is positioned in member 62 above the center line of the recess and with the tip 83 projecting down into that recess a distance not greater than, and preferably equal to, the distance travelled by the punch holder 61 and its attached member 62 during the pinch trim action upon the intermediate article. The head portion of the punch is held in place by the overlying punch holder 61 whose downward movement causes the punch to function. As seen in FIG. 7, the punch tip 83 touches the upper surface of the portion of the sheet drawn into the shape of the intermediate article as soon as the die elements have closed to the point where no further metal displacement is to take place. Thereafter, as the punch trim action occurs, the punch tip pierces the intermediate article and forms the aperture 80 by displacement of the punched slug. For the purpose of removing this punched out slug a chute 84 of gradually increasing cross section in its downward direction is formed in the respective die member 54, pinch trim ring 51, base ring 50, supporting plate 33 and base plate 30, beneath the punch tip 83. The slug accordingly may fall freely to the surface of the piston 36, as shown, whereafter it may be removed as desired.

Having thus described the invention, it will be understood that I do not desire to be limited to the particular embodiment as shown, since many modifications may be made, and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A one-piece hollow sink rim guard of generally semicircular cross section throughout formed of sheet metal and having an intermediate straight portion, a first leg portion extending at a right angle to said intermediate portion, a second leg portion extending at a right angle to said intermediate portion and parallel to said first leg' tion joined at arcuate corners with a pair of parallel side legs projecting at right angles to said intermediate portion comprising, providing an irnperforate flat metallic sheet of generally rectangular configuration, placing said sheet within a press between relatively movable platens respectively mounting a pinch-rim die extending continuously in the form of a pair of guards having the respective side legs of each guard joined in prolongation of the opposite side legs of the other guard and a die recess of a form commensurate with said die, arranging said sheet symmetrically between said die and said recess, moving said platens relatively toward each other into contact with said sheet and simultaneously drawing metal from the peripheral edge region of said sheet inwardly toward said die and stretching metal from the central portion of said sheet outwardly toward said die, continuing the relative movement of said platens and pinch trimming from the remainder of said sheet an intermediate article comprising two guards joined to each other, removing said intermediate article from said press and subsequently dividing said intermediate'article into two similar guards by transversely separating a pair of parallel :legs of said intermediate article at the mid-points thereof.

4. A method as defined in claim 3 including forming a plurality of apertures in said intermediate article during said continuing relative movement of said platens and with the location of said apertures being such that upon subdivision of said intermediate article each of said two guards will have identically arranged apertures therein.

References Cited in the file of this patent UNITED STATES PATENTS 1,808,731 Ireland June 2, 1931 2,038,637 Brey Apr. 28, 1936 2,261,793 Broomham Nov. 4, 1941 2,413,591 Sturdy Dec. 31, '1946 2,422,952 Dakin June 24, 1947 2,778,032 Meehan Jan. 22, 1957 2,961,663 Lenz Nov. 29, 1960 

